K2-136 c
K2-136 c
confirmed planet • updated: 2023-04-10
K2-136 c orbits the star K2-136, which is smaller and cooler than our Sun. Scientists spotted it using the transit method, which detects planets by measuring tiny dips in starlight when a planet crosses in front.
This page summarizes a catalog entry. If a measurement is missing, it is not shown or guessed. Some values can differ slightly between studies; when that happens, we describe the range rather than picking a favorite without evidence.
Scientific context
Scientific context: This profile layers interpretation on top of archival measurements. Modeled bands appear where direct detections (like spectra or transits) are not listed.
What we can’t claim: surface conditions, biology, or breathable atmosphere without direct spectra.
K2-136 c is a large planet — about 3 Earth radii and 18 Earth masses — orbiting its star every 17.3 days. Its orbit is nearly circular. The planet receives about 12 times more starlight than Earth, making it quite hot. Scientists estimate its temperature at around 470 Kelvin (about 386°F or 197°C), though this value has no error range listed. The star is about 74% the mass of our Sun and 68% its size.
Glossary (plain English)
- AU: the average Earth–Sun distance.
- Semi-major axis: the planet’s average distance from its star.
- Eccentricity: how oval the orbit is (0 = circle).
- Radial velocity: finding a planet by measuring a star’s tiny “wobble.”
- m·sin i: a minimum mass estimate; the true mass can be higher if the orbit is tilted.
- Equilibrium temperature: a rough estimate from starlight alone, not a surface reading.
K2-136 c was first reported in 2017 using the Transit method. The discovery is linked to observations from K2.
In transit work, astronomers watch for tiny, repeating dips in a star’s light as the planet passes in front of it. Follow-up observations help rule out false positives and refine the orbit.
The catalog lists an orbital period of about 17.31 days, a semi-major axis near 0.118 AU.
The orbit’s eccentricity is 0.05, which describes how stretched the orbit is. Because this is a multi‑planet system, stability is ultimately tested with dynamical (N‑body) fits; catalogs can update as models improve.
The archive reports a mass scale of 0.1 MJ.
A catalog radius is also listed, which (together with mass) helps constrain density and interior structure.
Why “m·sin i” shows up on RV planets
K2-136 c orbits K2-136.
A temperature near 4500 K places it on the sun-like side of the main sequence. The system is about 193.2 light‑years away.
Several key parameters are not present in this single catalog row.
Missing fields don’t mean the science is unknown—only that this particular snapshot doesn’t carry the values. As new observations arrive, archives often refresh these entries (and sometimes revise earlier numbers).
Scientists keep revisiting systems like this because each new instrument pass can tighten uncertainties: better timing improves the orbit, better spectra improves the star, and better follow‑up can confirm or refute competing solutions. Even when a planet is well‑established, refined stellar properties can shift the inferred planet size, temperature, and habitability context. Transit systems are especially valuable because they can be re‑observed for decades to detect subtle changes in timing or additional planets.